Automatic breech opening and closing mechanism for guns



Oct. 15, 1929. N. E. METHLIN 1,731,863

AUTOMATIC BREECH OPENING AND CLOSING MECHANISM FOR GUNS Filed Jan. 26, 1929 3 Sheets-Sheet 1 I5nnenfor (Itiornegs Oct. 15, 1929.

N. E. METHLIN 1,731,863

AUTOMATIC BREEGH OPENING AND CLOSING MECHANISM FOR GUNS 5 Sheets-Sheet 3 IIIA r Z F E 6 21 L1)? D I invenior CIHoz-neys.

Patented Get. 15, 1929 NICOLAS EMILIEN METHLIN, OF PARIS, FRANCE, ASSIGNOR TO SCHNEIDER & GIIEL, OF PARIS, FRANCE, A LIMITED JOINT-ETOCK COMPANY OF FRANCE AUTOMATIC BREEGH OPENING AN D CLOSING MECHANISM FOR GUNS Application filed January 26, 1929, Serial No. 335,297, and in France February 17, 1928.

It is known that automatic breech opening and closing mechanisms for guns exist in which the opening movements are produced during the return into battery position of the barrel and before this return is completed, by guiding the breech opening lever in a guide of suitable shape. The use of such guides presents however a certain number of disadvantages. The member carried by the lever and adapted to engage in the guide enters the latter at a fairly high speed when it is desired that all the movements for opening the breech, removing the spent cartridge case and ejecting the latter shall be completed, as is desirable, before the end of the return into battery position, in order that there will still remain sufiicient energy to permit these operations to be carried out; it is in fact known that it is necessary to damp the movement of the barrel at the end of the return into battery position.

Other automatic breech opening and closing mechanisms exist in which the energy for producing the various movements is not drawn exclusively from the return to battery recuperator, but is due partly to a spring or other auxiliary device attached to the fixed part and stressed during the recoil.

The object of the present invention is to provide an automatic breech opening and closing mechanism in which the movements for opening the breech, extracting and ejecting the spent cartridge cases, are completed before the return into battery position of the barrel is completed and in which the whole of the energy required for the movements for opening and closing the breech is drawn exclusively from the return to battery recuperator. The new mechanism permits the use of curved guides in the form of grooves to be dispensed with completely; it is consequently more simple in construction and avoids the possible occurrence of accidents caused by the breech operating lever becoming wedged in the guide.

According to the invention the abutment and guiding surfaces for the breech operating lever are formed upon a pivoting arm which only forms a guide groove during the movement of recoil and is adapted to be withdrawn in order to permit the automatic closure to take place under the action of a spring automatically stressed during the opening movement of the breech. The pivoting arm is provided at its front end with a simple bearing and abutment surface which is connected to another simple bearing surface for maintaining the breech controlling lever in the open position; the pivoting of the arm permits the latter to move into a position corresponding to the position then occupied by the breech operating member, in which position it forms a guide during the recoil for the projection on the said operating lever. The Withdrawal of the said arm permits to return into a position in which it forms a stop by its front edge lor the said projection. The pivoting movement of the arm also permits its withdrawal for the descent of the operating lever from the position in which it bears upon the arm corresponding to the open breech into the position it will occupy at the end of the closure of the breech.

In a practical embodiment of the invention the pivoting arm forming abutment of bearing surfaces during the return to battery position may be pivotally connected to a shock absorbing buffer. This embodiment of the invention is illustrated by way of example in the accompanying drawings.

Fig. l is a longitudinal elevation with a part in section along the axis of the automatic breech closure device.

Figs. 2, 3 and 4 are corresponding plans of the parts showing the members in three different positions of operation.

Fig. 5 is a transverse elevation of a part; the section being taken along the line 55 in Fig 1.

Figs. 6 and 7 are cross-sectional elevations taken along the lines 66 and 7-7 in Figs. 1 and 2.

Fig. 8 is a longitudinal elevation with a part in section along the axis of the automatic breech closure device and showing the gun in battery with the breech open.

In these figures A is a gun barrel of any type in which the breech block B, in the example shown, is of the type having concentric threads the operating member for this breech block being formed by a lever C keyed upon ashaft c the geometric axis of which coincides with that of the threads. The barrel is shown mounted upon a cradle D upon which'it recoils, which cradle is provided with trunnions (Z in the known manner, by means of which the said cradle is pivotally mounted on the gun carriage.

The breech opening and closing movements are obtained during the return to battery of the barrel, under the action of the encounter of the operating lever C with the special abutment and guiding member which forms the subject of the invention. This member is formed by an arm E pivotally connected to the nonrecoiling part by a shaft which is vertical when the cradle is in the horizontal position. This shaft instead of being mounted upon a fixed support is, in the particular embodiment of the invention described, mounted in a fork F formed at the end of a spring shock absorber or buffer adapted to make a slight movement of recoil in a cylinder F a spring F normally tends to maintain the fork E, which forms a bearing, in the position shown in the figures, that is to say slightly projecting upon the cylinder F The pivoting arm E is arranged so as to form during the recoil a guide for a spring pin C, located in the handle of the breech lever C. For this purpose the arm may be of Lshape in cross section as shown in Figs. 5, 6 and 7 that is to say, it may comprise a vertical web 0 and two horizontal flanges e 6 At rest, when the breech is closed, the springpin C is engaged (by projecting outside the lever C) between the flanges e c of the arm. The upper face of the flange 6 will serve as will be seen hereinafter, as bearing surface for the pin C, in order to maintain the breecn open when its opening movement has been completed and until the mo ment when the automatic closure is produced.

The arm E terminates at its back end in a vertical bearing surface 6 which will form' a stop for the pin C, at the desired moment during the return to battery, and will then serve as a bearing surface during the commencement of the opening of the breech un-- til the moment when the spent cartridge case is loosened and ejected.

The pivoting movement of the arm in the direction away from the cradle is limited by an abutment beak 03,, carried by an arm D formed as a projection upon a cradle l). The pivoting movement towards the cradle is limited by a spring buffer D the spring constantly tending to return the arm into the normal guiding and abutment position it occupies in Figs. 1 and 2.

The automatic closing device comprises a fixed part formed by a cylinder I-I secured to the barrel, in which cylinder moves a piston I, a spring J being interposed between the said piston and the rear end I-L, of the cylinder; the piston is pivotally connected by its rod and by means of a connecting-rod C to the breechlever C.' Thepivoting arm E is adapted, after the return to battery, the automatic opening of the breech and the loading of the gun, to be withdrawn into a position in which the spring pin C, no longer bears upon the upper flange c of the arm. This withdrawal is effected by means of a pin K carried by a shaft K pivoting in bearings K formed asprojections upon the cradle and carrying a handle K The pin K bears upon a boss 6, formed beneath the flange e, of the arm, by means of which boss it exerts a pressure upon the said arm and compresses the spring buffer D The device described operates in the following manner:

The members being in the position shown in Figs. 1 and 2, when the shot has been fired the barrel recoils, taking with it the small recuperator H-I. During the recoil the spring pin 0,, lodged in the handle of the operating lever, is guided betweenthe flanges 0 c of the arm E. The vertical web 6 is not arranged to follow the axial plane of the arm from which its front end commences; it is situated obliquely so as to connect with the front edge of the vertical bearing surface 6 It follows as a consequence that the spring pin C during the first part of the recoil, will be guided and gradually withdrawn inside the handle of the operating lever until it escapes from the web 6 of the arm. At this moment, under the action of the spring, the pin will be returned into its normal position so that when the return to battery takes place it abuts against the bearing surface 6 WVhen the barrel returns to battery posi- -tion, the pin C encounters the bearing surface 6 the lever C is compelled to turn about its shaft thus causing the breech to open by its rotation in the barrel which continues its forward travel. The pin C first of all slides from top to bottom along the bearing surface 6 making the lever pass from the position I into the position II. During this movement the breech begins to open.

During the following ascending movement of the pin C the lever passes from the position II into the position III during which period the cartridge case is loosened.

The ejection of the cartridge case will be effected during the period when the lever passes from the position III into the position IV, and it is easy to see that the path travelled during this movement isextremely small on account of the rotation about adjacent points of the intersection between the axes III and IV. In other words, the

cartridge case will be ejected while the breech block describes the required angle during its opening movement but at a fairly high speed, the lever travelling a very short distance during this time.

It is in fact seen that the cartridge case is loosened during the time the lever bears upon the vertical surface e while this lever is still adjacent to the vertical; then the lever takes up forward inclinations while its end arrives in the neighbourhood of the crest of the surface 6 To be precise the arrangement of a vertical bearing surface 6 followed by a horizontal bearing surface 6, permits the loosening and ejection of the cartridge case to be effected under the best possible conditions.

When the spring pin 0, has reached the crest of the vertical bearing surface 6 the opening movement of the breech is completed. The return to battery can thus be terminated, the breech block being held open by means of the pin C bearing upon the upper face of the flange 6 During the time when the pin C travelled over the vertical support 6 the axis of the lever C travelled the distance 00. At the same time the attachment c of the connecting-rod C to the lever C travelled over the smaller distance 02 It follows from this that the piston I returned into the cylinder H, compressing the spring J. The members then occupy the position shown in Fig. 8 which is a sectional elevation similar to that shown in Fig. 1. The breech is completely opened and the small recuperator is stressed so as to be able to secure the automatic closure of the breech when, by withdrawing the arm E, the pin C has been permitted to lose its support upon the upper face of the flange 6 of the arm. This withdrawal of the arm is effected, as stated above, by means of the pin K operated by means of the handle K Fig. 3 shows the arm E withdrawn by the pressure of the pin K, thus permitting the pin C to descend on account of the pull exerted by the spring J which expands and returns into the position shown in Fig. 1. The operator having released the handle. K the arm E returns into its position and engages upon the pin C (Figs. 1 and 2).

In this movement of return to battery the impact of the operating lever C against the bearing surface 6 is slightly damped by the shock absorber F to which the arm E is pivotally connected.

Claims 1. An automatic breech opening and closing mechanism for guns, characterized by an abutment and guiding member for the operating lever (C) of the breech block, comprising a simple bearing and sliding surface (e for opening the breech, removing the cartridge-case and extracting the latter, said surface being connected to a simple bearing surface (6 for keeping the breech in the open position during the end of the movement of return to battery of the barrel, these two surfaces (6 6 being formed upon a pivoting arm (6) forming a guide for the lever during the movement of recoil and adapted to be withdrawn in order to permit the automatic closure under the action of a spring (J) stressed during the opening movement.

2. An automatic breech opening and closing mechanism as claimed in claim 1, wherein the movement of oscillation of the pivoting arm (E) is limited outwards by a fixed stop (al carried by an arm (D forming a projection upon the cradle (D) and inwards by a spring buffer (D which normally keeps the arm in the position in which it serves as a guide during the recoil for the operating lever and as a bearing member during the opening movements of the breech, the member for withdrawing the arm formed by a pin (K) pivoted to the cradle, being adapted to take support upon the said spring buffer (D In testimony whereof I have signed this specification.

NICOLAS EMILIEN METHLIN. 

